Distance and direction determining system



May 10, 1938. H. SCHARLAU DISTANCE AND DIRECTION DETERMINING SYSTEM Filed June 25, 1935 INVENTOR HANS SCHARLAU ATTORN EY Patented May 10, 1938 UNITED STATES PATENT OFFICE DISTANCE AND DIRECTION DETERMINING SYSTEMI Hans Scharlau, Berlin, Germany, to

Teleflmken Geaellschaft fiir Drahtlose Telegraphic 111. b. 11., Berlin, Germany, a corporation of Germany Application June 25, 1935, Serial No. 28,252 In Germany July 5, 1934 11 Olflms. (Cl. 250-11) This invention relates to distance and direcbase line for a system of triangulation such that tion determining systems and is particularly conthe distance from a reflecting object may also be cerned with means to be mounted on board a very accurately indicated, vessel, an-aircraft or other conveyance for pro- The two receiving antennae may be rotatively jecting a radio beam against either natural or mounted so as to provide the necessary adjustartificial objects from which it may be reflected ment for causing their directional axes to interback to points adjacent the beam projector, and sect one another at different distances from the further means for detecting the reflected beams ship. A uni-control device may be embodied in and for indicating the distance and-the direction the apparatus so that both receiving antennae of the reflecting object. maybe adjusted simultaneously and uniformly. 1

- My invention may be used either to avoid col- If the two receiving antennae are mounted symlisions between vessels or to determine the altimetrically with reference to the axis of the vessel, tude at which an airplane may be flying. It is then the fleld or region which may be searched not, however, limited to such uses. for the purpose of indicating reflecting objects For direction finding with the aid of electroor dangerous obstacles may be held within amore 15 magnetic waves, apparatus has been provided in or less restricted angular range along the course the past in which the intensity of the incoming to be navigated- When energy radiated by the signal could be measured. Although known detransmitter is reflected back by some object in vices have proven fairly satisfactory for direction the path of the vessel then the direction and disfinding they were'not so useful for distance detertance of that object may be accurately deter- 20 mination. They were usually more or less complimined by the angles which the axes of maximum cated and required the use of a formula in order signalling strength make with the base line beto make a distance-calculation from any instrutween the two receiving antennae. ment readings that might be available, based on If my distance and direction finding apparatus the intensity of the incoming signal. I have is to be u d as an aid to aerial on, then 25 found, however, that radio energy may be so propthe transmitter may b mounted so as 110 p j ct a agated and reflected that, when received at two beam downwardly and the receiving antennae difierent points simultaneously, a simple calcumay als be ted, say, near the wing tips and lation could be made based upon principles of with their directional axes aimed toward the triangulation. It is, therefore, among the objects r und he y to iv indication of altitude at so of my invention to provide mechanical means which the airplane may be flying. As an alterwhereby the desired distance determinations may native a a e the receiving antennae may be easily read on indicators suitably calibrated be mounted one near the bow and the other near in units of distance. the stern of an airshipv It is another object of my invention to provide According to one embodiment of my invention 35 apparatus for distance and direction determinat i preferable to P v de separate receiving ndition which may be conveniently mounted on cator means in connection with each receiving board a. vessel for giving warning of the apantenna where great altitudes are to be deterproach of another vessel, the presence of an icemined. A uniform angular a justment of the 4 berg, reef, or any dangerous object. directional receivers is possible and both instru- 40 In carrying out my invention I preferably ments will exhibit like reflections or audible remount on board a vessel a suitable transmitter sponse. Whe e t altitude is low it ay be dehaving an antenna system which is combined sirable to show difierences between the signal-rewith means for directing a beamwithin the limits sponsive indications or readings of instruments of an acute angle. To one side and to the other separately operated from the two antennae and 45 of this beam projecting antenna system I also thus to obtain an indication of the lateral posimount a pair of receivers each having sharply tion, or the dip, or the inclination of the airplane focussed antenna systems or energy collecting when making alanding. This feature may have devices. The directional characteristic of each particular utility in the operation of bringing 5, of these receiving antennae is coordinated with down heavy hydroplanes on the water, or when 5 that of the other in such manner that a definite landing a Zeppelin. The utmost advantage is, of indication may be made as to the distance at course, to be obtained when my invention is so which their directional axes meet. Since the utilized under conditions of poor visibility. distance between these two receiving antennae My invention as regards the details of its conmay be very accurately determined, it forms the struction and operation may be best understood 55 upon reference to the accompanying drawing in which I Figure 1 represents diagrammatically an arrangementof the essential units of mydistance and direction finding system as when mounted aboard a ship for scanning an object along side;

Fig. 2 shows an alternative arrangement in which the field to be scanned lies .immediately ahead of the bow of the ship;

Fig. 3 shows diagrammatically one arrange-.

' The output energy from the transmitter T is preferably impressed upon an antenna system having a suitable reflector i whereby a beam of energy may be projected within the limits of any desired acute angle such as defined by the broken lines 4. Within the scope of this beam any existing object R having reflective properties may be caused to reflect back beams of energy 5 and 6 which can be intercepted by the receiving antennae i and 8. The energy so collected by the receiving antennae may then be utilized in a radio receiver l5, or a pair of such receivers, and indications may then be impressed upon any suitable responsive device, such as the earphones P.

The distance of the object R from the vessel V may be accurately determined upon reference to the angles which the beams 5 and 6 make with a base line joining the foci of the two energy collectors I and 8. The means for measuring these angles may be as shown in the other figures of the drawing. When the energy collectors are so adjusted as to obtain a maximum'signalling energy response, it is then that angular determinations may be made for showing the distance as well as the direction of the reflecting object R.

It is known that the object R need not be artificial in order to possess reflecting properties. Natural objects like rocks, icebergs, derelicts, other vessels, and, in fact, any dangerous obstacles in the path of a vessel may, and usually do, have reflecting properties.

Fig. 2 illustrates an alternative arrangement of my invention for providing protection against collision. Here the transmitter with its radiating antenna system I is so mounted, preferably near the bow of -a ship, that a beam of radio energy may be directed within the limits of lines I. If, then, any portion of the beam is reflected back along the lines 5 and 6 on account of the presence of a reflecting object R, then the reflected energy may be received upon the directional antennae i and 8. These antennae are preferably of the type which has parabolic reflectors so that the directional axis may be well defined. In order to vary the directional axis of each reflector I preferably mount the antenna and reflector on pivots 9. I then provide control arms III which may be swung on thepivots 9. At the end of each control arm I provide linkages ii connecting with a member I! which may be suitably rotated to produce a variable distance 0i ntersection of the antenna axes. At one end of the member i2 1 may provide a pointer i3 cooperatively positioned in respect to a scale II which may be calibrated either in terms of distance or of the angles which the receiving antenna axes make with a base line. The details of the receiving system which may be employed in connection with the receiving antennae have not been shown in Fig. 2, as they may be well understood from the showing of Fig. 1, or, possibly, from Fig. 4 presently to be described.

Referring now to Fig. 3, I show another modification in which the transmitter T may be the same as shown in Fig. 1. The transmitting antenna system includes a reflector I and the beam projected therefrom may be confined within the zone between the lines 4. The axis of such a beam is indicated as 4'. The presence of a reflecting object in the path of the beam l-will bedenoted by the reflection of energy along the lines 5 and 6, which energy is caused to impinge upon two reflectors 3 and again reflected toward a receiving antenna system it having parabolic energy collectors. The reflectors 3 may be mounted upon pivots 9 and their. directional characteristics may be adjusted by means of the lever arms iii, the linkages ii and the adjusting member I! upon the end of which is also mounted a pointer or other indicator I 3 in cooperative association with a scale it. The adjustment of the reflectors 3, as shown in Fig; 3, may be caused to double the significant angles and hence to increase the accuracy of the scale The receiving apparatus to whichthe receiving antennae i6 may be connected is shown at II.

Fig. 4 shows an aircraft or airplane having a fuselage A and wings W. The equipment of my invention may be installed with a transmitting antenna and directional reflector I for projecting a beam within the limits of the lines i1 and i1. Some of the energy so projected may be reflected back by the surface of the ground G along the lines l8 and i8 respectively. Auxiliary reflectors i9 may be mounted near the wing tips. The directional effect of these auxiliary reflectors i9 may be varied by pivoting the same at i. The control arms III are shown in this figure as mechanically coupled by the linkages Ii to the control member i2. This member abo has a pointer l3 arranged to move along the scale ll. The energy impinging upon the reflectors ll may again be directed against the energy collectors 20 and thence lead to suitable receivers 2i. In this case I preferably employ a separate indicating device or instrument 22 in connection with each receiver 2 I.

Banking of the airplane would be indicated by an unequal intensity of the received signal on the two receiving antennae 20 so that the readings on the two instruments 22 would not then be the same. If the reflectors l9 were to be mounted fore and aft, then a difference between the indications as provided on the two indicators 22 would be of assistance in determining the dip. The altitude may simultaneously be indicated by calibrating the scale il in terms of height.

Among the applications of my invention may be mentioned its practical use on vessels which navigate extensively along coastal regions and the mouths of rivers or where there are numerous beacons and lighthouses. If such beacons obtaining simultaneous and joint control of the directional effect of the receiving antennae 1 and 8 or of the reflectors 3 or I9, it,will be readily understood by those skilled in the art that this uni-control may also be obtained through the use of electrical means, if desired.

Many modifications of my invention not here in specifically described will suggest themselves to those skilled in the art in view of the basic idea herein disclosed. The particular embodiments herein shown are, therefore, to be considered as merely examples of apparatus which may be otherwise varied without departing from the spirit and scope of my invention.

I claim:

1. In a distance and direction determining system, a radio beam projector mounted aboard a vessel and adapted to transmit energy suitable for reflection by natural and artificial objects, a pair or energy collectors mounted aboard the same vessel and having sharply focussed directional characteristics, means for varying the angular relationship between the directional axes of said collectors, energy translating means for indicating the intensities of the energy picked up by said collectors when said energy emanates from said projector and is reflected back to said co1lectors,and means for indicating the angular relationship between the directional axes of said collectors when said axes are adjusted to give maximum response in said energy translating means 2. A system in accordance with claim 1 and having means fordirectly indicating the distance between said projector and one of said reflecting objects as a function of the angular relationship between the directional axes of said collectors when the latter are adjusted to give maximum response in said energy translating means.

3. A system in accordance with claim 1 and having means for indicating the direction of one of said reflecting objects as a function of the angle between the directional axis of one of said energy collectors and a base line joining the foci of the two said energy collectors.

4. A system in accordance with claim 1 and further characterized in that said energy collectors are symmetrically mounted in reference to the axis or radiation of said radio beam projector.

5. In a system for warning 2. navigator of the dangerous proximity of an object with which his vessel might collide, a transmitter mounted aboard said vessel and having a directional radio beam projector adapted to be aimed along the vessel's course, receiving apparatus having two sharply focussed energy collecting devices connected thereto, said devices being rotatively ad iustable so that the axes of their directional characteristics may meet at a variable distance from the vessel, means for indicating the intensity of the radio energy collected by said devices, and means operable, when said collected energy is a maximum, for indicating the distance from said vessel of an object by which said energy is reflected upon said collecting devices after propagation from said projector.

6. A system in accordance with claim 5 and having a uni-control device for simultaneously rotating said energy collecting devices into suitable position for obtaining a maximum response in said intensity indicating device.

'7. In an altitude meter, means for projecting a radio beam downwardly from an aircraft, a receiver having two separated radio energy collecting antennae so mounted on said aircraft as to receive ground reflections of said energy, unicontrol means for simultaneously varying the directive characteristics of said antennae to obtain a maximum response in said receiver, anda scale-and-pointer indicating device operatively associated with said uni-control means and callbrated in units of altitude measurement.

til

8. Apparatus in accordance with claim 7 and 4 having means for indicating a difierence between the respective responses to energy collected by one said antenna in relation to the energy collected by the other said antenna.

9. In a distance determining system, a radio beam projector mounted aboard a vessel and adapted to transmit a modulated or interrupted carrier wave suitable for reflection by natural or artificial objects, a pair of reflectors mounted aboard said vessel and so positioned as to receive re-radiated energy from said natural or artificial objects, a radio receiver having an antenna system suitably disposed to receive energy reflected by said pair of reflectors, means for simultaneously adjusting said reflectors so as to produce a maximum response in said receiver, and means for causing an indication to be given by the adjustment of said reflectors at the time of maximum receiver-response, said indication being in terms of distance separating said projector from said natural or artificial objects.

10. A distance determining system comprising a radio enezzgy projector mounted aboard a vessel and adapted to transmit a wave suitable for reflection by an intercepted object, a pair of directional energy collectors mounted aboard said vessel and spaced apart by a distance such as to form the base line in a. system of triangulation where the other two sides or the triangle are constituted by the directional axes 01' said energy collectors respectively, receiving means connected to said energy collectors and means for varying the angles subtended between said base line and said other lines of the triangle while causing said receiving means to respond to the energies collected, thereby to indicate the directional setting of said energy collectors suitable for maximum receiver response to energy reflected by said object.

11. A distance determining system in accordance with claim 10, and having a pointer-andscale mechanism connected to said directional energy collectors and arranged to indicate the distance separating said intercepted object from the base line or the triangulationsystem as a function of the angles respectively subtended between each of said directional axes of said energy 

